my (或 his 等) lips are sealed

used to convey that one will not discuss or reveal something

無可奉告

put (或 set) the seal on

give the final authorization to

最終授權；最終認可

the UN envoy hopes to set the seal on a lasting peace.

聯合國特使希望持久和平能確定下來。

seal someone's (或 something's) fate

irrevocably determine or cause a bad or unpleasant outcome for someone (or something)

注定命運（常指產生不幸或不愉快的結局）

set (或 put) one's seal to (或 on)

mark with one's distinctive character

給…蓋印；打上顯明的烙印

it was the Stewart dynasty which most markedly set its seal on the place.

正是斯圖亞特王朝在這個地方標上了它顯明的印記。

seal off

To close tightly or surround with a barricade or cordon

封鎖：用路障或封鎖線使關得嚴實或包圍

An unused wing of the hospital was sealed off.

一個未啟用的醫院側廳被封鎖了